Mold on recently repotted orchids

[arleneg]

A few weeks ago, I repotted my Paph. Ho Chi Minh (has new growth, possibly a spike), Onc. William Kirsh 'bread & butter, and Den. smilliae seedling. This morning, I noticed a small white hairy patch on top of the medium (coconut coir and perlite mix). Since I recently repotted, I was just thinking of spraying fungicide. But then, I feel I should repot them in another medium (bark and perlite). And, yet, I'm hesitant about repotting...afraid of stressing the orchids.

Please advise. I'm not sure how to handle this. Spray or repot??

[Cynthia, Prescott, AZ]

Did you fertilize shortly before seeing the mold? If so, leach the pot well with water and then cut down on the concentration of fertilizer, Paphs especially need less fert. My preference would be to use a fungicide sprayed only on the top of the mix. Repotting again would put additional stress on the roots that, on this occasion, doesn't seem justified. Since the coir and perlite is relatively slow draining, just pouring the solution into the pot should be fine. RD20, Physan 20, or probably pure 3% Hydrogen Peroxide should work.

[arleneg]

Hi Cynthia,

I did notice the mold a few days after fertilizing. After much thought, I did spray the top of the medium last night.

Should I just leach the pot with water or with solution? It wasn't quite clear if one or both should be done.

Thanks.